Subject: Viridian Note 00131: Fuel Made From Carbon

Key concepts: biotech, methanol, carbon-dioxide,
vaporware, Carbondale

Attention Conservation Notice: People in Carbondale are doing something strange with carbon dioxide and an artificial liver.

Links: New Scientist magazine, 29 January 02000

Entries in the "Dead Mike" Design contest:

Some stranger named Mike is publicly celebrating his mortality:

Viridian contests archive:

This contest expires February 15, 02000.

(((bruces remarks: NEW SCIENTIST is a darling of Viridian readers, many of whom sent in this report. The estimable, however, took the trouble to *fully annotate* the note, in fine Viridian style. His remarks follow.)))

From:^^^* (Brian Jenkins)
Subject: Upstream from the Fuel Cell

Key concepts: biotech, methanol, carbon-dioxide reduction,

Attention Conservation Notice: It's a description of a technology that doesn't quite work yet.

"Burning backwards

"Could cunning chemistry keep carbon emissions in check?" ((( "Cunning" is surely one of virtues most deeply admired by Viridians.)))

"An enzyme that breaks down alcohol in the liver could be used to recycle carbon, rather than pumping ever more into the atmosphere, say chemists in Illinois. They have developed a more efficient way of turning the greenhouse gas carbon dioxide into methanol using the enzyme.

"Invented by Bakul Dave and Robyn Obert of the
Southern Illinois University in Carbondale, the process effectively reverses the chemistry of burning. It promises to be a highly efficient way to produce methanol, a clean-burning fuel that can be used to power cars. What's more, if the energy needed to drive the process came from sources that don't generate CO2, this fuel could be produced and used without adding to the greenhouse effect.

"To make methanol, the liver enzyme and two bacterial
enzymes are embedded in a sponge-like, glassy material, which is placed in water. When CO2 is bubbled through the water, one of the bacterial enzymes, formate dehydrogenase, converts CO2 into formic acid. Then another, formaldehyde dehydrogenase, transforms the formic acid into formaldehyde. Finally, alcohol dehydrogenase, which normally helps our livers to detoxify alcohol, completes the reaction by turning the formaldehyde into methanol.

((( Now all we need is one more enzyme, and we'll all be talking on solar-fueled boozephones.)))

"Each of the enzyme reactions is reversible, so to
drive the process in the right direction, the Illinois team adds a fourth, electron-donating ingredient called nicotinamide adenine dinucleotide (NADH).

"The spongy glass, a substance called a silica sol-
gel, is the key to the reaction's success. It contains millions of microscopic pores that act as mini-reactors. By mixing the enzymes with the liquid gel, Dave and Obert successfully locked them into the structure. 'When it solidifies, the enzymes get trapped,' says Dave. 'The enzymes can't get in or out, but the small reactants can,' he says. So CO2 and NADH can get in, and methanol can diffuse out.

((( I like the idea of "spongy glass". I wonder what it feels like.)))

"To make the process practical, the NADH will have to
be recycled by constantly replenishing the electrons it feeds to the enzymes. Dave and Obert say this might be possible if the sol-gel is made from materials which conduct electricity and feed electrons back into the system. 'The idea is that you'd feed in current directly,' says Dave. (...)

(((This can't be much harder than making a pump-less fuel cell the size of a postage stamp. )))

"If Dave and Obert can solve the remaining problems,
it might be possible to recycle the CO2 from, say, power stations." (...)

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O=c=O O=c=O O=c=O O=c=O O=c=O O=c=O O=c=O O=c=O O=c=O